Yayoi – the 78th Head of Household of the Suzuka Clan – is a mystic with a tremendous power over the spirits. Of course, along with great power comes those with the desire to steal it! Enter Ura, who wants to become the King of the Demons. He comes to the human world to challenge Yayoi, but ends up stripped of his powers – and is sealed away as a black cat instead! Although Ura is still hell-bent on “eating” Yayoi’s power, the unlikely pair find themselves caught up in an adventure they never imagined!
A fantasy series for teen girls, Mugen Spiral is composed mostly of one-shot stories that involve Yayoi defeating demons with the help of Ura, a demon she seals away in cat and/or human form until he needs to bail her out. It’s better than it sounds, since the stoic and very powerful Yayoi isn’t the type of heroine that needs to be rescued often, and Ura is a very unlikely white knight. It’s also mercifully light on both zany gags and dark melodrama, two extremes that fantasy series tend to get caught in, though there are just enough touches of both to keep things interesting.
The magic and fantasy elements, such as the demon world Ura comes from and the nature of Yayoi’s powers, aren’t elaborated on very much. Most of the conflict comes courtesy of demons, including Ura, who show up to consume Yayoi’s powers in order to become the next Demon King. The chapter-by-chapter situations are a little underwhelming (because Yayoi is so powerful, she normally just falls for tricks), but both Yayoi and Ura are likable characters, and seeing the banter between them and the chemistry build on a chapter-by-chapter basis makes this more fun than it ought to be. Yayoi is very serious and has a habit of reading more into Ura’s intentions than he would like, which of course Ura plays off as annoying. There’s not a whole lot of romance between the two of them until the very end, but anyone who felt short-changed in the main storyline should be more than pleased with the excellent bonus story at the end of the volume.
There is no overarching story, and what seems like a developing plot winds up unresolved in the end (Ura wants to save his dad from a deadly curse, which never happens). There is a three-chapter arc involving a struggle with Ura’s dark magic brother (another story with a cliffhanger that doesn’t go anywhere), and… well, a lot of other plot threads and story hints that never quite get resolved. It’s easy to tell that it was one of the artist’s first ongoing series, and also one that was subject to a lot of editorial pressure and perhaps an early ending.
Overall, this reads a lot like a mediocre series, and it is. The stories are only okay, and it ultimately doesn’t go anywhere. Fantasy fans might be a bit disappointed by the lack of definition in those elements as well, but Yayoi and Ura make up for a lot of weaknesses, and make this a pretty fun light read in the end. The omnibus treatment makes this a great value, too.